Reproducibility of allergen-induced early and late asthmatic responses

BACKGROUND: Constant-dose allergen inhalation challenges are frequently used to examine the effect of antiasthma drugs on the allergen-induced early and late asthmatic responses. The end-point measurements in such studies are the maximal early and late percent decreases in the forced expiratory volume in 1 second (FEV1). OBJECTIVE: Our purpose was to observe the reproducibility and to determine the sample sizes required for such studies.